Tracking for outdoor Augmented Reality (AR) applications has very demanding requirements: It must deliver an accurate registration with respect to a given coordinate system, be robust and run in real time. Despite recent improvements, tracking still remains a difficult problem, particularly outdoors. Recently, mobile platforms, such as mobile phones, tablets, etc., have become increasingly attractive for AR. With the built-in camera as the primary sensor, phones facilitate intuitive point-and-shoot interaction with the environment.
Most outdoor tracking systems rely on inertial sensors to improve robustness. Even though some modern smart phones integrate a linear accelerometer, it is of little help in typical AR scenarios since it only delivers translational motion. Instead, most successful approaches rely on gyroscope sensors that measure rotations, which are primary sources for tracking instabilities.
A panoramic tracker may be used for tracking a mobile platform's orientation. The panoramic tracker may be integrated, e.g., into a system with sensors, such as satellite positioning systems, compasses linear accelerometers and gyroscopes to improve the system's robustness.
A panoramic tracker requires the generation of a panoramic map that is compared to a current image captured by the mobile platform to track the orientation of the mobile platform with respect to the map. Most existing approaches to panorama creation involve an offline process, which is undesirable. While real-time approaches to panorama creation exist, they suffer from problems such as high computational costs that render the approaches unsuitable for use with mobile platforms with limited processing power. Accordingly, improvements for creating panoramic content are desired.